Conventionally, there are provided analog cellular systems and digital cellular systems, examples of which are known as personal digital cellular telecommunication systems (PDC) and personal handyphone systems (PHS). Upon reception of incoming calls from calling parties, portable telephones produce prescribed incoming call sounds to notify users or subscribers of reception of incoming calls. As incoming call sounds, portable telephones conventionally produce beep sounds, which may be offensive to ears of users. Recently, portable telephones produce melody sounds as incoming call sounds, which are substituted for conventional beep sounds.
However, melody sounds produced by portable telephones are monotonous because melody sounds may correspond to simple musical tones of prescribed musical tunes that are constant in tonality and have poor variations and poor expressions. That is, conventional portable telephones are disadvantageous in that users easily loose interests in hearing monotonous melody sounds for use in notification of reception of incoming calls.
This invention is made in consideration of the aforementioned circumstances, so it is an object of the invention to provide a portable telephone that is capable of producing incoming call melody sound having rich variations and rich expressions.